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Keywords: railway track, numerical modelling, stationary method, cyclic moving load, dynamics, elastoplascity.

Summary

The numerical study of railway track behavior, when taking into account soil behaviour and the effects of cyclic moving loads is very demanding in terms of the computational effort. This is even more restrictive when studying the structure behaviour subjected to many loading cycles or the influence of parameter variability.

Thus, the numerical study presented in this paper seeks to implement a new method to enable a decrease in the computational time using the finite element method for railway structures that are subjected to moving loads. We have used a Eulerien formulation of the problem which gives us the state of the railway after different load cycles. This method is based on the stationary approach and on the changing of the coordinate system for which the simulation is carried out. This means that the global system of coordinates is now defined by the moving load and not by the structure, as in classic finite element simulations.

Thus, the purpose of this paper is to enhance the existing stationary method with the implementation of inertial effects, called in the paper dynamic effects, and the periodicity induced by the sleepers.

The implemented algorithm in the Cast3m code and the new developments were validated using published results. In order to check the effectiveness of this method for railway applications, this approach was tested and compared with classic dynamic finite element simulations. For the study of railway applications subject to a cyclic moving load, the gain in computational time is over ninety percent. The effect of the load speed is very well captured by the new implementation of dynamic effects in the stationary method. The railway deflections increase with the increase in the speed of the axle load. Nevertheless, the stationary approach for the application of moving loads to railway structures leads to a small underestimation of residual deformations after loading. The shortcomings of the method are the limitation to constant load (speed and amplitude), the validity just for the subsonic regime and the fact that spatial variability cannot be introduced in the method.

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Front Page Browse CCP CSETS CTR IJRT Other Authors Search Purchase Guide FAQ Contact us	Civil-Comp Proceedings ISSN 1759-3433 CCP: 96 PROCEEDINGS OF THE THIRTEENTH INTERNATIONAL CONFERENCE ON CIVIL, STRUCTURAL AND ENVIRONMENTAL ENGINEERING COMPUTING Edited by: B.H.V. Topping and Y. Tsompanakis Paper 3 Stationary Approach for the Modelling of the Ballast Track Behaviour subject to Cyclic Loading S. Costa D'Aguiar¹ and P. Sicsic² ¹Innovation and Research Department, Infrastructure Mechanics Group, Paris, France ²Ecole Polytechnique Palaiseau, France doi:10.4203/ccp.96.3 purchase the full-text of this paper Full Bibliographic Reference for this paper S. Costa D'Aguiar, P. Sicsic, "Stationary Approach for the Modelling of the Ballast Track Behaviour subject to Cyclic Loading", in B.H.V. Topping, Y. Tsompanakis, (Editors), "Proceedings of the Thirteenth International Conference on Civil, Structural and Environmental Engineering Computing", Civil-Comp Press, Stirlingshire, UK, Paper 3, 2011. doi:10.4203/ccp.96.3 Keywords: railway track, numerical modelling, stationary method, cyclic moving load, dynamics, elastoplascity. Summary The numerical study of railway track behavior, when taking into account soil behaviour and the effects of cyclic moving loads is very demanding in terms of the computational effort. This is even more restrictive when studying the structure behaviour subjected to many loading cycles or the influence of parameter variability. Thus, the numerical study presented in this paper seeks to implement a new method to enable a decrease in the computational time using the finite element method for railway structures that are subjected to moving loads. We have used a Eulerien formulation of the problem which gives us the state of the railway after different load cycles. This method is based on the stationary approach and on the changing of the coordinate system for which the simulation is carried out. This means that the global system of coordinates is now defined by the moving load and not by the structure, as in classic finite element simulations. Thus, the purpose of this paper is to enhance the existing stationary method with the implementation of inertial effects, called in the paper dynamic effects, and the periodicity induced by the sleepers. The implemented algorithm in the Cast3m code and the new developments were validated using published results. In order to check the effectiveness of this method for railway applications, this approach was tested and compared with classic dynamic finite element simulations. For the study of railway applications subject to a cyclic moving load, the gain in computational time is over ninety percent. The effect of the load speed is very well captured by the new implementation of dynamic effects in the stationary method. The railway deflections increase with the increase in the speed of the axle load. Nevertheless, the stationary approach for the application of moving loads to railway structures leads to a small underestimation of residual deformations after loading. The shortcomings of the method are the limitation to constant load (speed and amplitude), the validity just for the subsonic regime and the fact that spatial variability cannot be introduced in the method. purchase the full-text of this paper (price £20) go to the previous paper go to the next paper return to the table of contents return to the book description purchase this book (price £130 +P&P)
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